In the field of continuous mail handling, it is well-known in the art to provide systems which automatically weigh and meter mail pieces of different thickness. For example, as shown in U.S. Pat. No. 3,877,531, issued to Storace et al., Apr. 15, 1975, and assigned to the assignee of the present invention; there is disclosed a continuous mail sorting, weighing and postage imprinting system, wherein mixed mail pieces of different thickness are serially fed to a weighing station, where the mail pieces are individually weighed for the purpose of calculating the postage needed for mailing purposes, and then fed to a postage imprinting station, where postage is imprinted on the individual mail pieces.
As is generally shown and described in the aforesaid patent, and disclosed in greater detail in U.S. Pat. No. 3,894,734, issued to Sette et al., July 15, 1975, and assigned to the assignee of the present invention; it is well-known in the art to provide document decelerating mechanisms at weighing stations for slowing downstream movement of respective mail pieces for weighing purposes. In the Sette et al. patent there is described a decelerating mechanism which comprises a pair of cooperatively acting fingers, operative between open and closed positions, wherein the fingers converge toward one another when disposed in the closed position to provide a progressively restrictive passageway for incoming mail pieces. When the mail pieces contact the fingers, the fingers are moved by the mail pieces against the resistance of springs associated with the respective fingers. The springs tend to hold the fingers in their closed position. After the fingers decelerate the respective mail pieces to a complete halt, the fingers are separated to deposit the mail pieces upon the weighing platform of the scale for weighing purposes.
In the above described document weighing apparatus, it has been found that even when the mass of the respective finger members has been reduced as much as is possible consistent with maintaining stiffness of the fingers, the relatively thin mail pieces of a random group of mail pieces of different thickness cannot deflect the fingers against the resistance of the associated springs. This occurs due to the relatively thin, and thus light in weight, mail pieces not impacting the fingers with sufficient force to separate the fingers against the tension of the springs; as a result of which the fingers do not exert decelerating forces on the opposed major surfaces of the mail pieces. Rather, the mail pieces bounce back from the finger members to move upstream within the passageway.
Of course, the relatively thick mail pieces of the random group of mail pieces of different thickness are decelerated as discussed in Sette et al. Accordingly:
an object of the present invention is to provide improved apparatus for weighing documents of different thickness serially fed to a scale;
another object is to provide document weighing apparatus including a scale and improved means for decelerating downstream movement of respective documents serially fed to the scale; and
yet another object is to provide means for decelerating movement of documents serially fed to a scale platform, including a pair of flexure springs mounted for movement between document decelerating and non-decelerating positions.